1. Technical Field
The present invention generally relates to methods and systems for strain measurement, and more particularly to a system and method for uniform and localized wall thickness measurement using fiber optic strain sensors.
2. Discussion of Background Art
Fiber optics have been employed to monitor corrosion in several different forms. A number of applications employ fiber optics to monitor the strain generated within reinforced concrete due to build up of corrosion products. Others relate to the impact of corrosion on metal coated fibers or fibers doped with compounds that fluoresce in the presence of a target chemical species. However, these techniques require exposure of the fiber to the corrosive fluids.
An externally mounted fiber optics system by Fiber Optics Systems Technology, Inc. is described in “Direct Assessment of Corrosion Using Fiber Optic Sensors,” NACE, 2007, Paper no. 07385, wherein the system employs Brillouin spectrum analysis. Similarly, WIPO Patent Application No. WO2003078932A1 is directed to a system for the monitoring of large structures using Brillouin spectrum analysis. However, such systems do not employ Fiber Bragg Grating (FBG) sensors for uniform and localized wall thickness measurement.
Finally, a fiber optic system employing external FBG sensors to measure the strain applied to structural joints is described in U.S. Pat. No. 7,660,496, assigned to Schlumberger Technology Corporation. Again, such systems do not employ Fiber Bragg Grating (FBG) sensors for uniform and localized wall thickness measurement.